MOP
Maintenance Operations Protocol specifies message protocol for
network loopback assistance, network bootstrap, and remote
console functions.
MSCP
Mass Storage Control Protocol is used in Digital disks and tapes.
ms
Millisecond (10e-3 seconds)
NVRAM
Nonvolatile RAM, on the KA675/KA680/KA690. This is 1 Kb of
battery backed-up RAM on the SSC.
PC
Program Counter or R15
PCB
Process Control Block is a data structure pointed to by the
PR$_PCBB register and contains the current process’ hardware
context.
PFN
Page Frame Number is an index of a page (512 bytes) of local
memory. A PFN is derived from the bit field <23:09> of a
physical address.
PR$_ICCS
Interval Clock Control and Status, IPR 24
PR$_IPL
Interrupt Priority Level, IPR 18
PR$_MAPEN
Memory Management Mapping Enable, IPR 56
PR$_PCBB
Process Control Block Base register, IPR 16
PR$_RXCS
R(X)eceive Console Status, IPR 32
PR$_RXDB
R(X)eceive Data Buffer, IPR 33
PR$_SAVISP
SAVed Interrupt Stack Pointer, IPR 41
PR$_SAVPC
SAVed Program Counter, IPR 42
PR$_SAVPSL
SAVed Program Status Longword, IPR 43
PR$_SCBB
System Control Block Base register, IPR 17
PR$_SISR
Software Interrupt Summary Register, IPR 21
PR$_TODR
Time Of Day Register, IPR 27, is commonly referred to as the
Time Of Year register or TOY clock.
PR$_TXCS
T(X)ransmit Console Status, IPR 34
PR$_TXDB
T(X)ransmit Data Buffer, IPR 35
PSL, PSW
Processor Status Longword is the VAX extension of the PSW
(Processor Status Word). The PSW (lower word) contains
instruction condition codes and is accessible by nonprivileged
users; however, the upper word contains system status
information and is accessible by privileged users.
QBMBR
Q22–bus Map Base Register found in the CQBIC determines the
base address in local memory for the scatter/gather registers.
QDSS
Q22–bus video controller for workstations
Glossary–3
